Treatment of rubber



Patented Feb. 6, 1934 UNITED STATE PATENT OFECE TREATMENT OF RUBBER NoDrawing. Original application October 13, 1930, Serial No. 488,560.Divided and this application December 10,

14 Claims.

This invention relates to the treatment of rubber and similarvulcanizable materials, more particularly to treatment of the same withcertain derivatives of reaction products of secondary aromatic aminocompounds and aliphatic ketones. The invention also relates to theproducts of such treatment. This case is a division of case Serial No.488,560, filed Oct. 13, 1930.

An object of this invention is to provide materials having the propertyof retarding the deterioration of rubber.

Other objects will be apparent from the following detailed description.

Reaction products of secondary amino compounds and aliphatic ketones maybe prepared by reacting the amino compound and the ketone either with orwithout the aid of a suitable catalytic dehydrating agent. By this ismeant that high molecular weight ketones and amines or" high boilingpoint do not require the use of catalysts for economic production ofreaction products, but that with low boiling amines and ketones thereaction products cannot be prepared economically without the use of asuitable catalytic agent. Examples of products within the invention arethe reaction products of acetone and diphenylamine, acetone and phenylalphanaphthylamine, acetone and phenyl beta-naphthylamine, acetone anddiphenyl ethylene diamine, acetone and mono ethyl aniline, methyl ethylketone and phenyl alpha-naphthylamine, mesityl oxide and phenylalpha-naphthylamine, acetone and diphenyl formamidine, mesityl oxide andphenyl beta-naphthylamine, acetone and diortho tolyl guanidine acetoneand diphenyl guanidine, acetone and p-p' (dinaphthylamino) diphenylmethane, acetone and ortho tolyl biguanide. Their preparation isillustrated by the following procedures:

Example A.The reaction between acetone and diphenyl amine is preferablycarried out at relatively high temperatures and high pressures in thepresence of a dehydration agent, such as iodine, which also has acatalytic effect on the reaction. The amount of acetone may vary fromone to three moles per mole of diphenylamine. For example 320 pounds ofdiphenylamine, 220 pounds of acetone, 600 grams of iodine are heatedduring 20 hours at approximately 220 C. The pressure is approximately600 pounds per square inch at this temperature. An iron autoclave may beused with or without agitation. At the end of about 20 hours thecontents are cooled and the excess acetone and water formed aredistilled ofi. The remaining product is a dark brown 1932. Serial No.

liquid which may be used as such or further purifled. The reaction timemay be shortened by raising the temperature, for example at a temperature of 260 C. a reaction time of 12 hours is sufiicient. It hasalso been found that increasing the amount of iodine shortens the timeof reaction, for example the use of 1900 grams of iodine allows asatisfactory reaction at 220 C. in about 12 hours. Instead of usingiodine, hydrochloric acid may be used.

Example B.Reaction product of acetone and phenyl beta naphthlamine: Amixture of 219 grams phenyl beta naphthylamine, 696 grams acetone and 10grams of iodine are heated at approximately 210 to 220 C. during 33hours. The pressure at this temperature is approximately 600 pounds persquare inch. The crude reaction product is filtered through glass Wooland the excess of acetone and the water formed during the reaction areremoved by distillation. 7

ExampZe C.-The reaction product of acetone and phenylalpha-naphthyl-amine. This chemical is made according to the generalprocedure, namely by heating a mixture of 219 grams phenyl alphanaphthlamine, 116 grams of acetone, and 1.3 grams of iodine during 20hours at approximately 210 to 220 C. The product which remains afterremoval of acetone and water is a free-flowing oil.

Other ketones than those mentioned that may be used are phorone, diethylketone, monochlor-acetone, dichloracetone, aldol-acetone, diacetyl,acetyl-acetone, acetcnyl acetone, di-acetone alcohol,,ethylidene-acetone, allyl-acetone, aceto-phenone, benzal acetone,furfural-acetone, salicyl aldehyde-acetone, cyclo-pentanone,cyclohexanone. Other secondary amino compounds than those mentioned thatmay be used are dinaphthyl amines, naphthyl amino diphenyl, carbazole,p-nitro diphenylamine, 2,4 dinitrodiphenylamine, p-amino-diphenylamine,p-hyroxy-diphenylamine, sym-diphenyl-p-phenylene diamine, p-aminobenzyl-aniline, p-amino p-naphthylamino diphenyl methane,sym-dinaphthyl-p-phenylene diamine, phenyl beta naphthyl guanidine,phenyl o-tolyl guanidine, di-o-tolyl biguanide, mono phenyl biguanide,diphenyl biguanide. Certain dehydrating agents have been mentioned asgiving particularly effective results, but the invention generally isnot to be limited thereto. Other dehydrating agents may be used such ascalcium chloride. sulfanilic acid, phosphorus pentoxide, sodiumhydroxide, magnesium perchlorate, acetic acid, barium oxide, zincchloride, the amine addition product ZnClz,

group.

It is further to be understood that the term secondary aromatic aminocompound includes broadly any aromatic amino compound which comprises atleast one secondary amino nitrogen atom linked to an aromatic nucleus.

The present invention is illustrated with a preferred embodiment asfollows:

Example 1.Nitroso derivatives of the re ction product of acetone anddiphenylamine. The reaction product contains secondary amino nitrogenand therefore a nitroso derivative may be prepared. Theacetone-diphenylamine reaction product is dissolved in glacial aceticacid and a slight excess of a solution of sodium nitrite in Water isadded. The reaction mixture is then poured into a large volume of water,and the precipitate, the nitroso derivative, is filtered, washed anddried. This product possesses excellent antioxidant properties, as canbe seen from the following results in a carbon black rubber stock inwhich hexamethylene tetramine and diphenyl guanidine were used as theaccelerators:

+1.25 ports of Green tensiles Blank the nitroso derivative Aged tensiles168 hrs.

in oxygen 60 at 45# 1703 3023 75 at 457? 1432 2964 synthetic rubber,gutta percha, balata, or other rubber-like materials.

With the detailed description given above, it will be obvious thatmodifications will suggest themselves, for example other acceleratorsand suitable compounding ingredients may be used in conjunction with theantioxidants, all without departing from the principles of theinvention, and it is not desired to limit the invention otherwise thanas set forth in the appended claims.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. A process of treating rubber which comprises incorporating therewitha nitroso derivative of the reaction product of an aliphatic ketone anda secondary aromatic amino compound.

2. A process of treating rubber which comprises vulcanizing rubber inthe presence of a nitroso derivative of the reaction product of analiphatic ketone and a secondary aromatic amino compound.

3. A process of treating rubber which comprises incorpcrating therewitha nitroso derivative of the reaction product of an aliphatic ketone anda secondary aromatic amine.

4. A process of treating rubber which comprises vulcanizing rubber inthe presence of a nitroso derivative of the reaction product of analiphatic ketone and a secondary aromatic amine.

5. A process of treating rubber which comprises incorporating therewitha nitroso derivative of the reaction product or" an aliphatic ketone anda diarylamine.

6. A process of treating rubber which comprises vulcanizing rubber inthe presence of a nitroso derivative 01" the reaction product of analiphatic ketone and. a diarylamine.

7. A process of treating rubber which comprises incorporating therewitha nitroso derivative of the reaction product of acetone and adiarylamine.

8. A process of treating rubber which comprises vulcanizing rubber inthe presence of a nitroso derivative of the reaction product of acetoneand a diarylarnine.

9. A process of treating rubber which comprises incorporating therewitha nitroso derivative of the reaction product of acetone anddiphenylamine.

10. A process of treating rubber which comprises vulcanizing rubber inthe presence of a nitroso derivative of the reaction product of acetoneand dipnenylamine.

11. A rubber product resulting from the process set forth in claim 1.

12. A vulcanized rubber product obtained ac cording to the process ofclaim 2.

13. A rubber product resulting from the process set forth in claim 9.

14. A vulcanized rubber product obtained according to the process ofclaim 10.

WILLIAM P. res HORST.

